Resonance Raman Studies of Electron-Nuclear Coupling, Time Resolved Dynamics, and Magnetic Perturbations of Biomolecules

这项研究的目的是为了更好地了解生物分子在平衡和非平衡状态下的光学性质，并应用这些知识来阐明它们的作用机制。共振拉曼散射及其时间域模拟飞秒相干光谱(FCS)将用于探索肌红蛋白、血红蛋白和细胞色素c等血红素蛋白质中的电子和核结构/功能关系。相关技术，如电子吸收、泵浦-探测动力学、荧光、红外、核共振振动(NRVS)光谱和磁场微扰，也将用于表征样品，并帮助分配使用在前一个获奖期开发的新FCS技术揭示的低频运动。我们将利用同步自锁模钛宝石激光器来发展皮秒方法，以进行时间分辨的共振拉曼散射，并将动力学研究的范围扩展到ns区。动态吸收线形将用宽带连续谱技术测量，以便将含时共振条件适当地结合到由斯托克斯和反斯托克斯拉曼散射获得的振动弛豫的分析中。在了解共振FCS信号的绝对幅度和相位方面的理论进步将被用来消除非振荡背景信号，并允许改进对低频模式的检测。将进行相位和幅度激励剖面，以揭示与低频运动相关的不均匀性和非谐性。低温测量技术将被开发，以便FCS实验可以作为样品“玻璃”转变的函数来进行。这个项目具有广泛的影响，它奠定了蛋白质动力学领域的基础，这对我们对生命系统的基本理解至关重要。这项工作涉及应用于生物分子系统的最先进的基于激光的光谱学的发展。仪器和理论的发展将通过生产一种有效的FCS系统来增强进行时间分辨蛋白质动力学研究的基础设施，该系统通过使这项实验技术成为常规可访问的方式来扩大其使用。这些研究的意义不仅在于它们与生物科学的关系，而且还在于它们与我们对与凝聚相中的复杂系统相关的基本光-物质相互作用的理解。研究生和本科生将接受通过加强人力资源基础设施造福社会的尖端光学和生物技术方面的培训。该项目得到了生物科学局分子和细胞生物科学部的分子生物物理学计划和数学和物理科学局的物理司的支持。

The objectives of this research are to achieve a better understanding of the optical properties of biological molecules, both in and out of equilibrium, and to apply this knowledge to elucidate their mechanism of action. Resonance Raman scattering and its time domain analog, femtosecond coherence spectroscopy (FCS) will be used to probe the electronic and nuclear structure/function relationships in heme proteins like myoglobin, hemoglobin and cytochrome c. Related techniques such as electronic absorption, pump-probe kinetics, fluorescence, infrared, nuclear resonance vibrational (NRVS) spectroscopy, and magnetic field perturbations will also be used to characterize samples and aid in the assignment of the low frequency motions revealed using novel FCS techniques developed in the prior award period. Picosecond methodology will be developed using synchronized self-modelocked Ti:sapphire lasers to carry out both time resolved resonance Raman scattering and to extend the range of kinetic studies into the ns regime. Dynamic absorption lineshapes will be measured using broad-band continuum techniques so that time dependent resonance conditions can be properly incorporated into the analysis of vibrational relaxation obtained from the Stokes and anti-Stokes Raman scattering. Theoretical advances in understanding the absolute magnitude and phase of the resonant FCS signals will be exploited to eliminate non-oscillatory background signals and allow improved detection of low frequency modes. Phase and amplitude excitation profiles will be carried out to reveal inhomogeneities and anharmonicities associated with the low frequency motions. Low temperature measurement techniques will be developed so that FCS experiments can be carried out as a function of the sample "glass" transition. This project has a broad impact that underlies the field of protein dynamics that is crucial to our basic understanding of living systems. This work involves the development of state-of-the-art laser based spectroscopy that is applied to biomolecular systems. Instrumentation and theoretical development will enhance the infrastructure for doing time-resolved protein dynamics research by producing an effective FCS system that expands the use of this experimental technique by making it routinely accessible. These studies are significant not only in their relationship to the biological sciences, but also in their connection to our understanding of basic light-matter interaction associated with complex systems in the condensed phase. Graduate and undergraduate students will be trained in cutting edge optical and biological techniques that benefit society through the enhancement of the human resource infrastructure. This project is supported by the Molecular Biophysics Program in the Division of Molecular and Cellular Biosciences in the Directorate for Biological Sciences and the Division of Physics in the Mathematical and Physical Sciences Directorate.